Water-resistant gypsum formulations

ABSTRACT

Emulsions are provided which are useful in imparting water resistance to gypsum products. In one embodiment, the emulsions comprise a plurality of waxes, at least one saponified wax, a complexed starch, a polymerized alkyl phenol, and a small amount of a co-surfactant. In another embodiment, the emulsions comprise a single wax, a balanced dual surfactant system, a complexed starch and a polymerized alkyl phenol. Emulsions of this embodiment may be added to hot, even boiling, water without the emulsion separating or curdling. The emulsions of the present invention are stable for extended periods of time when stored at room temperature and do not require the addition of a bactericide. The emulsions of the present invention are pourable liquids at room temperature.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority under 35 U.S.C. §119(e) fromco-pending U.S. Provisional Application Serial No. 60/303,635, filedJul. 6, 2001, bearing an identical title.

FIELD OF THE INVENTION

[0002] The present invention relates to an additive useful in improvingthe water-resistance of gypsum products. The present invention alsorelates to an emulsion which includes an alkyl phenol, a wax, or acombination of waxes, and a complexed starch, the emulsion useful inimproving the water resistance of gypsum products. The present inventionfurther relates to a method of making the emulsion.

BACKGROUND OF THE INVENTION

[0003] Certain properties of gypsum (calcium sulfate dihydrate) make itvery popular for use in making industrial and building products;especially gypsum board. It is a plentiful and generally inexpensive rawmaterial which, through a process of dehydration and rehydration, can becast, molded or otherwise formed to useful shapes. The base materialfrom which gypsum board is manufactured is the hemihydrate form ofcalcium sulfate (gypsum), commonly termed stucco, which is produced bythe heat conversion of the dihydrate from which the water phase has beenremoved.

[0004] In the making of gypsum board, the gypsum slurry must flow onto apaper substrate. In a continuous process, the slurry/substratecombination is then sized by passing this combination between rollers.Simultaneous with this sizing step, a paper backing is positioned overthe sized gypsum slurry. Accordingly, the gypsum slurry must possesssufficient fluidity so that a properly sized gypsum board can be made.Fluidity refers to the ability of the gypsum slurry to flow.

[0005] It is also important to the manufacture of gypsum board, that thegypsum slurry be capable of being foamed to a limited extent.Foamability refers to this ability to be foamed. When the gypsum slurryand paper substrate are passed through the sizing rollers, a certainamount of the gypsum slurry must back flow and accumulate in the rollersnip so that a steady flow of gypsum is delivered to the sizing rollers.Foamability is important to this ability of the gypsum slurry to backflow at the rollers nip.

[0006] Because of the continuous nature of a gypsum board manufacturingprocess wherein the gypsum slurry flows onto a substrate which thenpasses through sizing rollers, the extent to which the gypsum slurryflows after it is sized is critical to maintaining the finished productdimensions of the gypsum board. The time at which the gypsum slurryceases its flow is referred to as the pre-set time. Therefore, pre-settime is an important property of the gypsum slurry. The set time of thegypsum slurry is also an important property. The set time refers to theamount of time it takes the gypsum slurry to be dried, under heat, tothe finished, solid gypsum board. As is well known in the art, in acontinuous gypsum board manufacturing process, it is important that thegypsum slurry possess a consistent set time.

[0007] Gypsum board absorbs water, which reduces the strength of thewallboard. Prior art products, like ordinary gypsum board, gypsum tile,gypsum block, gypsum casts, and the like have relatively littleresistance to water. When ordinary gypsum board, for example, isimmersed in water, the board quickly absorbs a considerable amount ofwater, and loses a great deal of its strength. Actual tests havedemonstrated that when a 2 inch by 4 inch cylinder of gypsum board corematerial was immersed in water at about 70° F., the cylinder showed awater absorption of 36% after immersion for 40 minutes.

[0008] Previous attempts to provide water-resistant properties to gypsumboard include incorporation of asphalt, metallic soaps, resins, and waxadditives into a aqueous gypsum slurry. The resulting materials weredifficult to use and the core properties difficult to control.Polysiloxane-based systems have also been used in attempts to impartwater-resistance to gypsum board. However, the polysiloxane-basedsystems are both expensive and difficult to use. A finished gypsumproduct has also been coated with water resistant films or coatings. Onespecific example of a past attempt to provide a water-resistant gypsumproduct is the spraying of a molten paraffin, wax or asphalt into anaqueous gypsum slurry.

[0009] Another example of a prior art attempt to provide a waterresistant gypsum product is the addition of an emulsion of wax, such asparaffin wax, and asphalt, in the relative proportions of from about 1part to about 10 parts of asphalt per part of wax to the aqueous gypsumslurry. Since the asphalt is a relatively poor solvent for paraffin waxand similar wax at ordinary temperatures, the solution formed at hightemperatures tends on cooling to deposit microscopic wax crystals on theasphalt-wax surface.

[0010] Polyvinyl alcohol has been used in an attempt to provide a roomtemperature system for use in adding water resistant properties togypsum. However, the polyvinyl alcohol system tends to rapidly separateand thus typically requires continuous mixing prior to use. The inherentinstability of the polyvinyl alcohol systems tends to producestratification of the compounds in the formulation. Therefore, thepolyvinyl alcohol systems tend to be compositionally inconsistent. Inaddition, because of destabilization into different phases, there isalso the potential for bacterial growth.

[0011] Accordingly, there is a need for an additive which is useful inimparting water-resistance to gypsum products, and which is economicalto apply. There is a need for a water-resistance additive which does notrequire the use of costly components such as polysiloxane. There is aneed for a stable, water-resistance additive. There is a further needfor a water-resistance additive which is stable at room temperature andwhich does not require heating prior to application to a gypsumsolution. There is still a further need for a stable water-resistanceadditive which does not require continuous mixing or agitation tomaintain its stability. There is yet a further need for a stablewater-resistance additive which does not require the addition of abactericide to control bacterial growth inherent in existing systems. Ofcourse, such additives should perform these functions without affectingfluidity, foamability, pre-set time or set time.

SUMMARY OF THE INVENTION

[0012] The present invention, in one embodiment, provides an emulsionwhich comprises a plurality of waxes, at least one saponified wax, acomplexed starch, a polymerized alkyl phenol, and a small amount of aco-surfactant. In another embodiment, the present invention provides anemulsion comprising a single wax, a balanced dual surfactant system, acomplexed starch and a polymerized alkyl phenol. Emulsions of thisembodiment may be added to hot, even boiling, water without the emulsionseparating or curdling. The emulsions of the present invention arestable for extended periods of time when stored at room temperature anddo not require the addition of a bactericide. The emulsions of thepresent invention are pourable liquids at room temperature.

[0013] The emulsions of the present invention are useful in impartingwater resistance to gypsum products. The emulsions of the presentinvention also include a fire retardant. The emulsions of the presentinvention may be used in the manufacture of conventional gypsum board,composites made using gypsum, such as gypsum/fiber composites, and othergypsum products.

[0014] The present invention also provides a method by which a singlewax emulsion, useful in imparting water resistance to gypsum products,can be manufactured.

DETAILED DESCRIPTION OF THE INVENTION

[0015] There is provided in accordance with the principles of thepresent invention an emulsion which is useful in impartingwater-resistance properties to gypsum products. The emulsions of thepresent invention may be added to mixtures of gypsum and water withoutadversely affecting properties of the mixture which are necessary to themanufacture of gypsum products such as gypsum board. Such propertiesinclude fluidity, foamability and set time.

[0016] Preparation of Emulsions

[0017] Emulsions were prepared by heating the wax and surfactants (“waxmixture”) in one vessel and the water, borate compound and corn starch(“water mixture”) in another vessel. Both mixtures were heated, withmixing, to about 185° F. (85° C.). Next, the wax mixture was poured intothe water mixture under mixing. The resultant mixture was then placed ina homogenizer. With homogenization it is preferred that a distributionof micelle diameters ranging from about 0.6 micron to about 1.8 micronbe achieved. However, the distribution of micelle diameters may rangefrom about 0.5 micron to about 2.5 micron. This level of homogenizationmay be attained, for example, by using a dual orifice homogenizeroperating at from about 2,000 to about 4,000 psig.

[0018] It is preferred that the homogenized mixture be cooled after thehomogenization step. It is most preferable that the homogenized mixturebe cooled from approximately 185° F. to about 100° F. This may beaccomplished by running the homogenized mixture through a cooling coilimmersed in water maintained at room temperature.

[0019] HLB Values

[0020] The hydrophilic/lipophlilic balance (“HLB”) value describes therelationship of a compound to its solubility in water. An emulsifierhaving a low HLB value will tend to be oil soluble and one having a highHLB value will tend to be water soluble. Typically, a water solubleemulsifier or blends thereof are used to make an oil/water emulsiontypical of those described herein, or to solubilize oils or waxes, or toobtain some measure of detergent action. Thus, the HLB value can be usedto describe or select the proper emulsifier or emulsifier system.

[0021] Where two or more components are combined, the HLB value of thecombination is the weighted average of the individual HLB values. Thefollowing formula may be used to calculate the HLB value of acombination of materials:${{{HLB}({combined})} = \frac{{Q_{1} \times ( {HLB}_{1} )} + {Q_{2} \times ( {HLB}_{2} )} + {\ldots \quad Q_{n} \times ( {HLB}_{n} )}}{Q_{1} + Q_{2} + {\ldots \quad Q_{n}}}};$

[0022] where,

[0023] Q₁=weight of material 1; HLB₁=HLB value of material 1

[0024] Q₂=weight of material 2; HLB₂=HLB value of material 2

[0025] Q_(n)=weight of material n; HLB_(n)=HLB value of material n

[0026] Test Specimens

[0027] Test specimens were made by mixing 50 grams of gypsum, 35.97grams of water, and 1.92 grams of a specified emulsion. For the control,no emulsion was added. Gypsum, water and, if added, emulsion, were mixedtogether and left to stand for one minute. This mixture was then mixedfor an additional 30 seconds. After this second mixing, the specimenswere subjected to fluidity testing.

[0028] Fluidity Test

[0029] The specimens mixed as provided above were poured out onto a flatsurface and the diameter of the resulting patty was measured. Thediameter of a patty is an index of the fluidity of the specimen. Thelarger the diameter, the more fluid the specimen.

[0030] Foamability Test

[0031] The foamability test is used to determine the affect of a waxemulsion on the stability of foam in a gypsum slurry. In this test, 0.60grams of a commercially available foamant and 2 grams of wax emulsionare weighed out. The foamant and the emulsion are placed into a blenderalong with 100 grams of water. The mixture is blended for 20 seconds. Atthe end of this blending step, the foam is immediately poured from theblender cup into a tared 150 ml beaker to overflowing. Any excess isstruck off the beaker. Any foam remaining in the blender cup is setaside. The foam density is determined by weighing the foam in the 150 mlbeaker. Two minutes after the blending has stopped, any liquid in theremaining foam in the blender cup is drained and discarded. A clean,tared, 150 ml beaker is filled with the remaining foam to overflowingand the excess is struck off. A second foam density is determined asdescribed above. For the emulsions of the present invention, foamdensities were acceptable and ranged from about 40 to about 65 grams per150 ml, for the measurements made at 20 seconds, and from about 10 toabout 45 grams per 1 50 ml, for the measurements made at 2 minutes.

[0032] Water Absorption Test

[0033] Patties made in the Fluidity Test were dried for at least 24hours at 110° F. At the end of this time, the patties were weighed andthe weight was recorded. The dried patties were then immersed in waterFor two hours. At the end of the two hour immersion, the patties wereweighed and this wet weight was recorded. Percent water retention wasthen calculated based on the difference between these two recordedweights.

[0034] Materials

[0035] Waxes useful in making the various embodiments of the presentinvention may be selected from any of the commercially known waxes whichhave a melting point of from about 120° F. to about 150°, and preferablyfrom about 135° F. to about 145°. Such waxes are typically of lowvolatility, exhibiting less than about a 10% loss in weight duringstandard thermogravimetric analysis. Also, the oil content of thesewaxes is typically less than about 1% by weight. These waxes are of arelatively high molecular weight, having an average chain length of C₃₆,that is a 36 carbon chain length, or greater.

[0036] In certain embodiments, it is useful to saponify one or more ofthe waxes. In this way, the saponified wax functions as an addedsurfactant. Waxes useful in this respect are limited to waxes having anacid value or a saponification value and a melting point greater thanabout 180° F. Saponification of such waxes may be accomplished bycombining the wax with a strongly basic material such as sodiumhydroxide or potassium hydroxide. Waxes which may be saponified in theemulsions of the present invention include montan wax, carnauba wax,beeswax, bayberry-myrtle wax, candelilla wax, caranday wax, castor beanwax, esparto grass wax, Japan wax, ouricury wax, retamo-ceri mimibi wax,shellac, spermaceti wax, sugar cane wax, wool-lanolin wax, and others.The amount of strongly basic material needed to saponify a wax may becalculated based on the saponification value of the wax. For example,the saponification value divided by 1000 equals the grams of potassiumhydroxide to add per gram of wax.

[0037] Starch used in the emulsions of the present invention iscomplexed starch. The starch may be complexed in situ, duringmanufacture of the emulsion, or the starch may be pre-complexed prior tobeing added to the emulsion. Starch is preferably complexed by mixingthe starch with a complexing agent such as a borate compound. Apreferred borate compound is sodium tetraborate decahydrate. Othercompounds useful in complexing starch include ammonium biborate,ammonium pentaborate, potassium pentaborate, potassium tetraborate, andlithium tetraborate, The starch useful in making the complexed starch ofthe present invention includes, but is not limited to, corn, rice,wheat, potato, sago and other starches. The ratio of borate complexinigagent to starch is important to the functionality of the complexedstarch in the emulsions. It has been found that the ratio may be as lowas 1:20, of borate to starch on a weight per weight basis, butpreferably 1:7. The ratio may be as high as 1:3.5, however it has beenfound that at this ratio, and higher ratios, a greater amount ofcomplexed starch is needed in the emulsion to maintain the balance ofdesired properties in the gypsum mixture and final gypsum product. Thesedesired properties include fluidity, foamability, and water resistance.

[0038] A co-surfactant may be used in embodiments of the presentinvention. These co-surfactants are added in small amounts, relative toother components in the emulsion, and are effective in helping tomaintain the stability of the emulsion. The co-surfactants includecalcium lignosulfonate, sodium lignosulfonate, and trisodium phosphate.

[0039] Incorporating alkyl phenols into the emulsions has been foundimportant to achieving low water absorption in the final gypsum product.Such alkyl phenols include long chain, C₂₄-C₃₄ (from 24 to 34 carbonchain length) polymerized methylene-coupled alkyl phenol, calciumphenates, long branched chain calcium alkyl phenols, long straight chaincalcium alkyl phenols and complex polymers of maleic acid with andwithout an amine group substitution. As used herein, the alkyl phenolsare identified by an arbitrary identification number as noted below.Identification No. Description Source 319A Complex polymer of maleicacid “Flozol 140” (no amine group substitution) Lubrizol Chem. Corp.Wycliffe, Ohio 319B Complex polymer of maleic acid “Flozol 145” (withamine group substitution) Lubrizol Chem. Corp. Wycliffe, Ohio 319CStraight chain, long chain alkyl Lubrizol Chem. Corp. phenol Wycliffe,Ohio 319D Calcium Phenate Lubrizol Chem. Corp. Wycliffe, Ohio 319EBranched chain, long chain alkyl Lubrizol Chem. Corp. phenol Wycliffe,Ohio 319H C₂₄-C₃₄ polymerized methylene- Lubrizol Chem. Corp. coupledalkyl phenol Wycliffe, Ohio

[0040] In certain embodiments which use a single wax additive, it hasbeen found that a dual surfactant system provides a stable emulsion atboth room temperature and elevated temperatures. Such stable emulsionsmay be added, for example, to hot or boiling water, without the emulsionseparating or curdling. The dual surfactant system uses a unique ratioof the component surfactants to provide an HLB value within a range ofabout 8.9 to about 14. It is preferred that the component surfactantseach have an HLB value greater than 6. One example of a dual surfactantsystem of the present invention is a combination ofdodecylisopropanolamine benzene sulfonate and a nonionic ethoxylatedaryl phenol. Dodecylisopropanolamine benzene sulfonate may be obtainedfrom Unichema, Wilmington, Del., under the trade name SD1121. Onenonionic ethoxylated aryl phenol is Ethiox 2938, available from EthoxCorp., Greenville, S.C. Alternatively, an alkoxylated fatty acid estermay be combined with the of dodecylisopropanolamine benzene sulfonate toform the dual surfactant system. One alkoxylated fatty acid ester isEthox 2914, also available from Ethox Corp., Greenville, S.C.

[0041] It has also been found that in certain embodiments of the presentinvention a dispersing aid, or fluidity modifier, is useful for themaintenance of the fluidity of the gypsum/emulsion mixture. Suchdispersing agents are strong lipophiles, which are, consequently, gooddefoamers. One such dispersing agent is poly(oxy-1,2-ethanedyl),alpha-phenyl-omega-hydroxy styrenate.

[0042] Multiple Wax Systems

[0043] In one embodiment of the present invention, an emulsion is formedby combining and homogenizing two waxes, a co-surfactant, an alkylphenol and a complexed starch. Table 1 below provides examples ofemulsions made according to this embodiment. Also, there is providedresults of testing the gypsum/emulsion mixture and gypsum product. Allmixtures and homogenization is were made, and tests were performed, asdescribed above. TABLE 1 MULTIPLE WAX SYSTEMS Component/ EmulsionEmulsion Emulsion Control Parameter A B C (no emulsion) (amount ofcomponent, grams) Wax 3816 134.0 132.0 130.0 Montan Wax 12.0 12.0 12.0319H 10.0 4.0 6.0 Sodium 4.0 4.0 4.0 lignosulfonate Water 239.0 237 237Borax 1.5 1.5 1.5 Corn Starch 6.5 6.5 6.5 KOH 3.0 3.0 3.0 % Water 1.077.76 −0.34 33.30 Retained Fluidity 3 inches 3.25 inches 3.25 inches 4inches

[0044] Wax 3816 is a hard paraffin wax, available from Honeywell/Astor,Duluth, Ga. In the emulsions described in Table 1, corn starch iscomplexed with sodium tetraborate decahydrate. Montan wax was saponifiedin situ by the addition of potassium hydroxide (KOH).

[0045] It has been found that the following ranges of componentpercentages, based on the total weight of the emulsion (% w/w), areuseful in embodiments of the multiple wax systems of the presentinvention. Component % (w/w) Wax 30-35 Saponified Wax  3-10 Alkyl Phenol0.5-10  Co-surfactant 0.5-5   Water 55-65 Starch 0.25-10   ComplexingAgent 0.25-10   Alkali 0.5-3  

[0046] The ratio of starch to complexing agent is maintained within therange described above. The actual amount of alkali required to saponifythe wax is dependent on the amount of wax and the saponification valueof the wax, also as described above.

[0047] The beneficial and synergistic effect of the combination ofcomponents can be best understood by reference to Table 2 below. In theemulsions described in Table 2, certain components were selectivelyeliminated from the emulsion formulation. Water absorbance for theseemulsions is compared to that for Emulsion C, described in Table 1.TABLE 2 SYNERGISTIC EFFECT OF EMULSION COMPONENTS Control Component/Emulsion Emulsion Emulsion Emulsion (no Parameter C D B E emulsion)(amount of component, grams) Wax 3816 130.0 132.0 132.0 132.0 Montan Wax12.0 12.0 12.0 12.0 319H 6.0 4.0 4.0 Sodium 4.0 4.0 4.0 4.0 ligno-sulfonate Water 237 241 237 243 Borax 1.5 1.5 1.5 1.0 Corn Starch 6.56.5 6.5 1.0 KOH 3.0 3.0 3.0 3.0 % Water −0.34 13.08 7.76 12.95 33.30Retained Fluidity 3.25 3 inches 3.25 3.25 4 inches inches inches inches

[0048] As Table 2 illustrates, comparing Emulsion C and Emulsion D, theomission of the alkyl phenol compound from the emulsion formulationresults in a surprising and unexpected increase in water absorption ofmore than one hundred percent. In other words, the use of the alkylphenol compound effectively reduces the water absorption of the gypsumproduct by two orders of magnitude. Also illustrated in Table 2 is theeffect of a change in ratio of starch to complexinig agent. Comparingthe results realized with Emulsion B and Emulsion E, the data shows thata 36 percent reduction in water absorbance can be achieved by varyingthe starch to complexinig agent ratio.

[0049] Single Wax Systems

[0050] In a further embodiment of the present invention, an emulsion isformed by combining and homogenizing a single wax, a dual surfactantsystem, an alkyl phenol and a complexed starch. Table 3 below providesexamples of emulsions made according to this embodiment. Also, there isprovided results of testing the gypsum/emulsion mixture and gypsumproduct. All mixtures and homogenizations were made, and tests wereperformed, as described above. TABLE 3 SINGLE WAX SYSTEMS Component/Emulsion Emulsion Emulsion Parameter F G H Control (amount of component,grams) Wax 3816 135.0 134.5 134.5 319H 4.0 4.0 4.0 Ethox 2914 14.0 12.012.0 SD1121 4.0 4.0 4.0 Water 240.0 240.0 240.0 Borax 0.5 0.5 0.5 CornStarch 2.5 5.0 5.0 % Water 1.24 −0.02 3.47 33.30 Retained

[0051] As illustrated in Table 3 above, a combination of a single wax, adual surfactant system, an alkyl phenol and a complexed starchsignificantly reduces the amount of water absorbed by the gypsumproduct. In Table 4 below, the effect of varying, or eliminating,certain components from this embodiment is illustrated.

[0052] It has been found that the following ranges of componentpercentages, based on the total weight of the emulsion (% w/w), areuseful in embodiments of the single wax systems of the presentinvention. Component % (w/w) Wax 33-38 Alkyl Phenol 0.5-10  FirstSurfactant of Dual 0.5-5   Surfactant System Second Surfactant of0.5-5   Dual Surfactant System Water 55-65 Starch 0.25-10   ComplexingAgent 0.25-10  

[0053] The ratio of starch to complexing agent is maintained within therange described above. The ratio of the first surfactant to the secondsurfactant in the dual surfactant system is determined based on acombined HLB value of from about 8.9 to about 14, as described above.TABLE 4 SYNERGISTIC EFFECT OF SINGLE WAX SYSTEM COMPONENTS Component/Emulsion Emulsion Emulsion Parameter F I J Control (amount of component,grams) Wax 3816 135.0 140.0 130.0 319H 4.0 10.0 Ethox 2914 14.0 12.0SD1121 4.0 4.0 Water 240.0 240.0 240.0 Borax 0.5 0.5 Corn Starch 2.5 3.5Cationic 18.0 Surfactant % Water 1.24 49.83 24.46 33.30 Retained

[0054] As illustrated in Table 4, the elimination of the alkyl phenolcompound resulted in a surprising and unexpected increase in the waterabsorption by the gypsum product. Also, even in the presence of thealkyl phenol compound, elimination of the dual surfactant systemresulted in a surprising and unexpected increase in the water absorptionby the gypsum product. In Emulsion J, a cationic surfactant wassubstituted on an equal mass basis for the dual surfactant system.

[0055] The single wax systems of this embodiment are useful in a widerange of gypsum product formulations. The systems of this embodiment areparticularly useful for addition to hot aqueous gypsum formulations.Where the emulsions of the prior art tend to separate and curdle uponaddition to hot aqueous formulations, the single wax systems of thisembodiment are stable in such formulations and do not separate or curdleeven on addition to boiling water.

[0056] A dispersion agent, as identified above, may be added to thesingle wax systems of this embodiment to improve the fluidity of anemulsion/gypsum/water mixture. The dispersion agent may be added at fromabout 0.025% to 2.00%, based on the total weight of the emulsion. Whenused, the dispersion agent is post-added, that is it is added after theemulsion has been formed.

[0057] The use of borates or trisodium phosphate in embodiments of theemulsions of the present invention imparts two additional benefits tothe gypsum products employing such emulsions. The borates and trisodiumphosphate are useful as fire retardant compounds and these compounds arenatural biocides. Therefore, incorporation of a fire retardant compoundinto a gypsum product can present certain advantages to the users ofthese gypsum products. Also, the emulsions of the present invention donot require the further addition of another biocide to prevent bacterialgrowth in the emulsions.

[0058] There has been disclosed in accordance with the principles of thepresent invention an emulsion and gypsum product made using such anemulsion. The emulsion is useful in imparting water resistance to thegypsum product. While certain embodiments and best mode of the presentinvention are described herein, these embodiments are merelyillustrative. It will be apparent to those skilled in the art thatmodifications may be made therein without departing from the spirit ofthe invention and the scope of the appended claims.

What is claimed is:
 1. An emulsion useful in providing water resistanceto a gypsum product, the emulsion comprising: a first wax, the first waxhaving a melting point of 120° F. or greater; a second wax having amelting point of 180° F. or greater, the second wax having asaponification value; an alkyl phenol; a co-surfactant, selected fromthe group consisting of sodium lignosulfonate, potassium lignosulfonateand trisodium phosphate; a strong alkali; water; and a complexed starch;wherein the strong alkali saponifies the second wax to provide asurfactant.
 2. The emulsion of claim 1 wherein the first wax has amelting point of from about 120° F. to about 150° F.
 3. The emulsion ofclaim 1 wherein the strong alkali is potassium hydroxide.
 4. Theemulsion of claim 1 wherein the alkyl phenol is a long chain C₂₄-C₃₄methylene coupled alkyl phenol.
 5. The emulsion of claim 1 wherein thecomplexed starch is a complex of sodium tetraborate decahydrate andstarch.
 6. The emulsion of claim 1 wherein the second wax is present inan amount ranging from about 3 percent to about 10 percent of the totalweight of the emulsion.
 7. The emulsion of claim 1 wherein theco-surfactant is present in an amount ranging from about 0.5 percent toabout 5 percent of the total weight of the emulsion.
 8. The emulsion ofclaim 1 wherein the complexed starch is present in an amount rangingfrom about 0.5 percent to about 15 percent of the total weight of theemulsion.
 9. An emulsion useful in providing water resistance to agypsum product, the emulsion comprising: a wax, the wax having a meltingpoint of 135° F. or greater; an alkyl phenol; a dual surfactant system,the dual surfactant system comprising a mixture of two surfactants suchthat a HLB value of the mixture is from about 8.9 to about 14; water;and a complexed starch.
 10. The emulsion of claim 9 wherein the wax hasa melting point of from about 135° F. to about 150° F.
 11. The emulsionof claim 9 wherein the alkyl phenol is a long chain C₂₄-C₃₄ methylenecoupled alkyl phenol.
 12. The emulsion of claim 9 wherein the dualsurfactant system is a mixture of dodecylisopropanolamine benzenesulfonate and a nonionic ethoxylated aryl phenol.
 13. The emulsion ofclaim 9 wherein the dual surfactant system is a mixture ofdodecylisopropanolamine benzene sulfonate and an alkoxylated fatty acidester.
 14. The emulsion of claim 9 wherein the complexed starch is acomplex of sodium tetraborate decahydrate and starch.
 15. The emulsionof claim 9 further comprising a fluidity modifier.
 16. The emulsion ofclaim 15 wherein the fluidity modifier is poly(oxy-1,2-ethanedyl),alpha-phenyl-omega-hydroxy styrenate.
 17. The emulsion of claim 9wherein the wax is present in an amount ranging from about 33 percent toabout 38 percent of the total weight of the emulsion.
 18. The emulsionof claim 9 wherein the dual surfactant system is present in an amountranging from about 1 percent to about 10 percent of the total weight ofthe emulsion.
 19. The emulsion of claim 9 wherein the complexed starchis present in an amount ranging from about 0.5 percent to about 15percent of the total weight of the emulsion.
 20. A gypsum slurry usefulin making a gypsum product, the gypsum slurry comprising: (a) calciumsulfate dihydrate; and (b) an emulsion comprising: a first wax, thefirst wax having a melting point greater than about 120° F.; a secondwax, the second wax having a saponification value; an alkyl phenol; aco-surfactant, the co-surfactant selected from the group consisting ofsodium lignosulfonate, potassium lignosulfonate and trisodium phosphate;a strong alkali; water; and a complexed starch; wherein the strongalkali saponifies the second wax to provide a surfactant.
 21. The gypsumslurry of claim 20 wherein the first wax has a melting point of fromabout 120° F. to about 150° F.
 22. The gypsum slurry of claim 20 whereinthe strong alkali is potassium hydroxide.
 23. The gypsum slurry of claim20 wherein the alkyl phenol is a long chain C₂₄-C₂₈ methylene coupledallkyl phenol.
 24. The gypsum slurry of claim 20 wherein theco-surfactant is sodium lignosulfonate.
 25. The gypsum slurry of claim20 wherein the co-surfactant is trisodium phosphate.
 26. The gypsumslurry of claim 20 wherein the complexed starch is a complex of sodiumtetraborate decahydrate and starch.
 27. A gypsum slurry useful in makinga gypsum product, the gypsum slurry: (a) calcium sulfate dihydrate; and(b) a wax emulsion comprising: a wax, the wax having a melting point of135° F. or greater; an alkyl phenol; a dual surfactant system, the dualsurfactant system comprising a mixture of two surfactants such that theHLB value of the mixture is from about 8.9 to about 14; water; and acomplexed starch.
 28. The gypsum slurry of claim 27 wherein the wax hasa melting point of from about 135° F. to about 150° F.
 29. The gypsumslurry of claim 27 wherein the alkyl phenol is a long chain C₂₄-C₃₄methylene coupled alkyl phenol.
 30. The gypsum slurry of claim 27wherein the dual surfactant system is a mixture ofdodecylisopropanolamine benzene sulfonate and a nonionic ethoxylatedaryl phenol.
 31. The gypsum slurry of claim 27 wherein the dualsurfactant system is a mixture of dodecylisopropanolamine benzenesulfonate and an alkoxylated fatty acid ester.
 32. The gypsum slurry ofclaim 27 wherein the complexed starch is a complex of sodium tetraboratedecahydrate and starch.
 33. The gypsum slurry of claim 27 furthercomprising a fluidity modifier.
 34. The gypsum slurry of claim 33wherein the fluidity modifier is poly(oxy-1,2-ethanedyl),alpha-phenyl-omega-hydroxy styrenate.
 35. A method of making anemulsion, the emulsion useful in providing water resistance to a gypsumproduct, the method comprising: (a) providing: a first wax, the firstwax having a melting point of 120° F. or greater; a second wax having amelting point of 180° F. or greater, the second wax having asaponification value; an allyl phenol; a co-surfactant, selected fromthe group consisting of sodium lignosulfonate, potassium lignosulfonateand trisodium phosphate; a strong alkali; water; and a complexed starch;(b) mixing the first wax, the second wax, the alkyl phenol and theco-surfactant to provide a first pre-mix; (c) mixing the strong alkali,water and complexed starch to provide a second pre-mix; (d) combiningthe first pre-mix and the second pre-mix to provide a mixture; and (e)homogenizing the mixture; wherein the homogenized mixture contains adistribution of micelles; and wherein the strong alkali saponifies thesecond wax to provide a surfactant.
 36. The method of claim 35 whereinthe distribution of micelles have a range of micelle diameters fromabout 0.5 microns to about 2.5 microns.
 37. A method for making anemulsion, the emulsion useful in providing water resistance to a gypsumproduct, the method comprising: (a) providing: a wax having a meltingpoint of 135° F. or greater; an alkyl phenol; water; and a complexedstarch; (b) mixing a plurality of surfactants to provide a dualsurfactant system such that the HLB value of the dual surfactant systemis from about 8.9 to about 14; (c) mixing the wax, the alkyl phenol andthe dual surfactant system to provide a first pre-mix; (d) mixing thewater and complexed starch to provide a second pre-mix; (e) combiningthe first pre-mix and the second pre-mix to provide a mixture; and (h)homogenizing the mixture; wherein the homogenized mixture contains adistribution of micelles.
 38. The method of claim 37 wherein thedistribution of micelles have a range of micelle diameters from about0.5 microns to about 2.5 microns.
 39. The method of claim 37 wherein thewax has a melting point of from about 135° F. to about 150° F.
 40. Themethod of claim 37 wherein the alkyl phenol is a long chain C₂₄-C₃₄methylene coupled alkyl phenol.
 41. The method of claim 37 wherein thedual surfactant system is a mixture of dodecylisopropanolamine benzenesulfonate and a nonionic ethoxylated aryl phenol.
 42. The method ofclaim 37 wherein the dual surfactant system is a mixture ofdodecylisopropanolamine benzene sulfonate and an alkoxylated fatty acidester.
 43. The method of claim 37 wherein the complexed starch is acomplex of sodium tetraborate decahydrate and starch.
 44. The method ofclaim 37 further comprising the step of mixing a fluidity modifier withthe emulsion.
 45. The method of claim 44 wherein the fluidity modifieris poly(oxy-1,2-ethanedyl), alpha-phenyl-omega-hydroxy styreniate.
 46. Agypsum product comprising: calcium sulfate dihydrate; and an effectiveamount of the emulsion of claim
 1. 47. A gypsum product comprising:calcium sulfate dihydrate; and an effective amount of the emulsion ofclaim 9.